Moscow offered to give New Zealand a nuclear submarine to help settle Russia's debt for Kiwi dairy products, a new book reveals.

Also offered in lieu of cash in the mid-1990s were MiG jets and tanks, says Clive Lind, author of a book to be published next month exploring 40 years of the multi-billion dollar New Zealand dairy sector up to the big industry merger that formed Fonterra.

Lind said he was "staggered" to hear during his research of the Russian offer of the sub to then-Prime Minister Jim Bolger and Dairy Board chairman Dryden Spring.

Lind is Fairfax New Zealand's editorial development manager and former editor of three Fairfax daily newspapers who already has 12 published books under his belt.

Told by Bolger that New Zealand had a nuclear-free policy, Moscow's response was to suggest "we tie it up in some port and connect it to the national grid", Lind said.

Russia and New Zealand tied the diplomatic relationship knot in 1944, and Russia's appetite for Kiwi agricultural products such as dairy products, meat, and wool, at times since elevating it to New Zealand's fifth-largest export market.

The Soviet Union dissolved in 1991 and after 1992 New Zealand's trade with Russia fell dramatically.

By 1993 it was heading north again, with Russia accumulating a large debt for dairy products and wool.